El polietileno de alto entrecruzamiento no reduce el desgaste en la artroplastia total de rodilla / Cross-linked polyethylene does not reduce wear in total knee arthroplasty

Objetivo: Comparar dos pares de fricción (metal/polietileno de ultra alto peso molecular [UHMWPE], metal/polietileno de alto entrecruzamiento) mediante análisis cuantitativo y cualitativo de partículas de polietileno en líquido sinovial a los 3 años postintervención en pacientes portadores de prótesis total de rodilla (PTR). Material y métodos: Se llevó a cabo un estudio de cohortes prospectivo, aleatorizado, con evaluación ciega incluyendo 25 pacientes a quienes se intervino de PTR de manera bilateral, con 6 meses de diferencia. A los 3 años postintervención, se realizaron artrocentesis de rodilla a 12 pacientes y se analizaron las partículas de polietileno. Resultados: No se hallaron diferencias significativas en el número de partículas generadas por los diferentes insertos de polietileno a los 3 años tras la implantación de una artroplastia total de rodilla (3.000×: x¯ entrecruzado=849,7; x¯ UHMWPE=796,9; p=0,63; 20.000×: x¯ entrecruzado=66,3; x¯ UHMWPE=73,1; p=0,76). Tampoco existen diferencias significativas entre los 2 tipos de inserto, entre la posibilidad de encontrar partículas de forma elongada (χ2=0,19; p=0,66) ni redonda (χ2=1,44; p=0,23). Sin embargo, la probabilidad de encontrar partículas de forma fibrilar es 3,08 veces mayor en el UHMWPE. Conclusiones: El polietileno altamente entrecruzado no reduce significativamente la generación de partículas de polietileno en aquellos pacientes intervenidos mediante una artroplastia total de rodilla, con muestras a 3 años postintervención

Aim: To compare two different types of inserts: Ultra-high molecular weight polyethylene (UHMWPE) and cross-linked polyethylene with a quantitative and qualitative study of polyethylene wear particles in synovial fluid 3 years after total knee arthroplasty. Material and methods: A prospective, randomized, controlled cohort study with blinded evaluation was carried out on 25 patients undergoing staged bilateral total knee replacement, 6 months apart. Knee arthrocentesis was performed on 12 patients 3 years after surgery, and the polyethylene particles were analyzed. Results: No significant differences were found in the number of particles generated by the two different types of inserts at 3 years from total knee arthroplasty (3,000×: x¯ cross-linked=849.7; x¯ UHMWPE=796.9; P=.63; 20,000×: x¯ cross-linked=66.3; x¯ UHMWPE=73.1; P=.76). Likewise, no differences in the probability of finding elongated (χ2=0.19; P=.66) or rounded (χ2=1.44; P=.23) particles in both types of inserts were observed. However, the probability of finding fibrillar particles is 3.08 times greater in UHMWPE. Conclusions: Cross-linked polyethylene does not significantly reduce the generation of polyethylene particles in patients with total knee arthroplasty, 3 years after the surgical procedure

Cross-linked polyethylene does not reduce wear in total knee arthroplasty. / El polietileno de alto entrecruzamiento no reduce el desgaste en la artroplastia total de rodilla.

AIM: To compare two different types of inserts: Ultra-high molecular weight polyethylene (UHMWPE) and cross-linked polyethylene with a quantitative and qualitative study of polyethylene wear particles in synovial fluid 3 years after total knee arthroplasty. MATERIAL AND METHODS: A prospective, randomized, controlled cohort study with blinded evaluation was carried out on 25 patients undergoing staged bilateral total knee replacement, 6 months apart. Knee arthrocentesis was performed on 12 patients 3 years after surgery, and the polyethylene particles were analyzed. RESULTS: No significant differences were found in the number of particles generated by the two different types of inserts at 3 years from total knee arthroplasty (3,000×: x¯ cross-linked=849.7; x¯ UHMWPE=796.9; P=.63; 20,000×: x¯ cross-linked=66.3; x¯ UHMWPE=73.1; P=.76). Likewise, no differences in the probability of finding elongated (χ2=0.19; P=.66) or rounded (χ2=1.44; P=.23) particles in both types of inserts were observed. However, the probability of finding fibrillar particles is 3.08 times greater in UHMWPE. CONCLUSIONS: Cross-linked polyethylene does not significantly reduce the generation of polyethylene particles in patients with total knee arthroplasty, 3 years after the surgical procedure.

Bloqueo ecoguiado de los nervios geniculados en el manejo analgésico de la artroplastia de rodilla: descripción de la técnica y resultados clínicos preliminares / Ultrasound-guided genicular nerve block for pain control after total knee replacement: preliminary case series and technical note

Introducción. La artroplastia total de rodilla (ATR) es una cirugía con un dolor postoperatorio moderado-severo. Los modelos Fast-Track emplean técnicas de infiltración local con anestésico con elevados volúmenes (100-150ml). Nos planteamos realizar el bloqueo de los nervios geniculados con bajo volumen de anestésico local. El objetivo de nuestro estudio es evaluar la distribución periarticular de estos bloqueos en un modelo humano (cadáver) y describir la técnica en un grupo preliminar de pacientes sometidos a ATR. Materiales y métodos. En la fase anatómica se realizó el bloqueo de 4 nervios geniculados (superomedial, superolateral, inferomedial e inferolateral) con 4ml de anestésico local con contraste yodado y azul de metileno en cada uno de ellos (16ml en total). Se realizó en cadáver fresco y se evaluó la distribución del medio inyectado mediante escáner y cortes coronales en sus 2 rodillas. La fase clínica incluyó a 12 pacientes programados para ATR. Se realizó, preoperatoriamente, el bloqueo ecoguiado de los 4 nervios geniculados y evaluamos su eficacia clínica mediante la valoración del dolor tras la reversión del bloqueo subaracnoideo y a las 12h de realizado el bloqueo. Se midió el dolor mediante escala numérica y se evaluó la necesidad de analgesia de rescate. Resultados. Se observó una amplia distribución periarticular del contraste por escáner que fue posteriormente evaluado en los cortes coronales. La distribución seguía la cápsula articular sin introducirse en la articulación, tanto en el fémur como en la tibia. En el grupo de pacientes, el dolor tras la reversión del bloqueo subaracnoideo fue de 2±1, precisando analgesia de rescate un 42% de los pacientes. A las 12h, el dolor según la escala numérica fue de 4±1, precisando analgesia de rescate un 33% de ellos. Conclusión. La administración de 4ml de anestésico local a nivel de los 4 nervios geniculados de la rodilla produce una distribución amplia periarticular. Nuestros datos preliminares en una serie de 12 pacientes sometidos a ATR parece ser clínicamente efectiva. A pesar de ello, son necesarios amplias series de casos y estudios comparativos con la analgesia mediante infiltración local que corroboren estos alentadores resultados (AU)

Introduction. Total knee arthroplasty (TKA) is an operation with moderate to severe postoperative pain. The Fast-Track models employ local infiltration techniques with anaesthetics at high volumes (100-150ml). We proposed a genicular nerve block with low volume of local anaesthetic. The aim of our study is to evaluate the periarticular distribution of these blocks in a fresh cadaver model and to describe the technique in a preliminary group of patients submitted to TKA. Materials and methods. In the anatomical phase, 4 genicular nerves (superior medial, superior lateral, inferior medial and inferior lateral) were blocked with 4ml of local anaesthetic with iodinated contrast and methylene blue in each (16ml in total). It was performed on a fresh cadaver and the distribution of the injected medium was evaluated by means of a CT-scan and coronal anatomical sections on both knees. The clinical phase included 12 patients scheduled for TKA. Ultrasound-guided block of the 4 genicular nerves was performed preoperatively and their clinical efficacy evaluated by assessing pain after the reversal of the spinal block and at 12h after the block. Pain was measured using the numerical scale and the need for rescue analgesia was evaluated. Results. A wide periarticular distribution of contrast was observed by CT-scan, which was later evaluated in the coronal sections. The distribution followed the joint capsule without entering the joint, both in the femur and in the tibia. The pain after the reversal of the subarachnoid block was 2±1, requiring rescue analgesia in 42% of the patients. At 12h, the pain according to the numerical scale was 4±1, 33% required rescue analgesia. Conclusion. The administration of 4ml of local anaesthetic at the level of the 4 genicular nerves of the knee produces a wide periarticular distribution. Our preliminary data in a series of 12 patients undergoing TKA seems to be clinically effective. Nevertheless, extensive case series and comparative studies with local infiltration techniques with anaesthetics are needed to support these encouraging results (AU)

Ultrasound-guided genicular nerve block for pain control after total knee replacement: Preliminary case series and technical note. / Bloqueo ecoguiado de los nervios geniculados en el manejo analgésico de la artroplastia de rodilla: descripción de la técnica y resultados clínicos preliminares.

INTRODUCTION: Total knee arthroplasty (TKA) is an operation with moderate to severe postoperative pain. The Fast-Track models employ local infiltration techniques with anaesthetics at high volumes (100-150ml). We proposed a genicular nerve block with low volume of local anaesthetic. The aim of our study is to evaluate the periarticular distribution of these blocks in a fresh cadaver model and to describe the technique in a preliminary group of patients submitted to TKA. MATERIALS AND METHODS: In the anatomical phase, 4 genicular nerves (superior medial, superior lateral, inferior medial and inferior lateral) were blocked with 4ml of local anaesthetic with iodinated contrast and methylene blue in each (16ml in total). It was performed on a fresh cadaver and the distribution of the injected medium was evaluated by means of a CT-scan and coronal anatomical sections on both knees. The clinical phase included 12 patients scheduled for TKA. Ultrasound-guided block of the 4 genicular nerves was performed preoperatively and their clinical efficacy evaluated by assessing pain after the reversal of the spinal block and at 12h after the block. Pain was measured using the numerical scale and the need for rescue analgesia was evaluated. RESULTS: A wide periarticular distribution of contrast was observed by CT-scan, which was later evaluated in the coronal sections. The distribution followed the joint capsule without entering the joint, both in the femur and in the tibia. The pain after the reversal of the subarachnoid block was 2±1, requiring rescue analgesia in 42% of the patients. At 12h, the pain according to the numerical scale was 4±1, 33% required rescue analgesia. CONCLUSION: The administration of 4ml of local anaesthetic at the level of the 4 genicular nerves of the knee produces a wide periarticular distribution. Our preliminary data in a series of 12 patients undergoing TKA seems to be clinically effective. Nevertheless, extensive case series and comparative studies with local infiltration techniques with anaesthetics are needed to support these encouraging results.

Proximalize osteotomy of tibial tuberosity (POTT) as a treatment for stiffness secondary to patella baja in total knee arthroplasty (TKA).

INTRODUCTION: Stiffness after a total knee arthroplasty (TKA) is one of the most common post-operative complications. The purpose of this study is the evaluation of the effectiveness of TT proximalization osteotomy of improving a lack of flexion and secondary pain in patella baja (infera) post-TKA. MATERIALS AND METHODS: Between April 2007 and July 2012, TT proximalization osteotomy was performed on 21 patients. The average preoperative flexion was 70° (in a range of 60-80). Clinical pre- and post-operative evaluations were performed with Knee Society Score, Western Ontario and McMaster Universities Arthritis Index scales and a satisfaction survey. Modified Blackburn-Peel index and Portner angle were used to evaluate patellar height. RESULTS: After an average follow-up of 35 months (range 18-48), an average flexion of 100° (range 90-100) and an overall satisfaction were obtained. Clinical scores improved significantly. The Blackburn-Peel index and Portner angle improved significantly from 0.3 (range 0.1-0.5) to 0.4 (0.3-0.5) and from 9 (3-15) to 12 (9-18), respectively. Three patients showed no signs of osteotomy consolidation. However, this was not linked to a lack of extension or an increase in local pain. CONCLUSION: TT proximalization osteotomy provides satisfactory results in improving a lack of flexion and pain in patella baja post-TKR.

Consenso SECOT-GEDOS sobre el control del dolor prequirúrgico en artrosis de rodilla y cadera / SECOT-GEDOS consensus on pre-surgical pain management in knee and hip arthrosis

Objetivo: Desarrollar recomendaciones basadas en la mejor evidencia y experiencia sobre el manejo del dolor en pacientes con artrosis de rodilla o cadera e indicación de artroplastia. Métodos: Las recomendaciones se emitieron siguiendo la metodología de grupos nominales. Se seleccionó un grupo director de expertos (5 traumatólogos y un anestesiólogo) que definieron el alcance, usuarios, apartados del documento, posibles recomendaciones, revisiones sistemáticas y se asignaron tareas. Se realizaron 3 revisiones sistemáticas sobre: la eficacia y seguridad de la analgesia prequirúrgica en relación al dolor posquirúrgico; la eficacia y seguridad de la analgesia preventiva, y sobre los factores prequirúrgicos que influyen en el dolor posquirúrgico. Los expertos redactaron los apartados y generaron las recomendaciones correspondientes. El nivel de evidencia y grado de recomendación se clasificaron según el modelo del Center for Evidence Based Medicine de Oxford y el grado de acuerdo por técnica Delphi (2 rondas). El Delphi se amplió a 39 traumatólogos y anestesiólogos. El documento completo circuló entre el grupo director para su última revisión. Resultados: Se generaron 21 recomendaciones. Incluye el manejo farmacológico específico, la evaluación y monitorización de estos pacientes que están en tratamiento, y el tratamiento preventivo del dolor posquirúrgico. Existió consenso mayor del 70% en 19 de ellas. Conclusiones: En el paciente pendiente de artroplastia de cadera o rodilla se debe hacer una correcta evaluación, seguimiento y manejo farmacológico y no farmacológico de los factores que predicen un mal resultado de la intervención, en particular del dolor prequirúrgico. Estas actuaciones pueden mejorar el dolor posquirúrgico y el resultado de la artroplastia (AU)

Objective: To develop recommendations, based on best evidence and experience, on pain management in patients undertaking total knee or hip replacement. Methods: Nominal group methodology was followed. A group of experts was selected (5 orthopedics, 1 anesthesiologist), who defined the scope, users, topics, preliminary recommendations, and 3 systematic reviews: efficacy and safety of pre-surgical analgesia regarding to post-surgical pain, efficacy and safety of pre-emptive analgesia and pre-operative factors of post-operative pain. The level of evidence and grade of recommendation was established using the Oxford Centre for Evidence Based Medicine, and the level of agreement with the Delphi technique (2 rounds). The Delphi was extended to 39 orthopedics and anesthesiologists. The whole document was reviewed by all the experts. Results: A total of 21 recommendations were produced. They include specific pharmacological treatment, as well as the evaluation and monitoring of patients on this treatment, and post-operative pre-emptive treatment. Agreement above 70% was reached in 19 recommendations. Conclusions: In patients undergoing total knee or hip replacement, a proper evaluation, follow-up, pharmacological and non-pharmacological treatment of predictors of poor surgical outcomes should be performed, especially those related to pre-operative pain. This can improve post-operative pain and surgery outcomes (AU)

SECOT-GEDOS consensus on pre-surgical pain management in knee and hip arthrosis.

OBJECTIVE: To develop recommendations, based on best evidence and experience, on pain management in patients undertaking total knee or hip replacement. METHODS: Nominal group methodology was followed. A group of experts was selected (5 orthopedics, 1 anesthesiologist), who defined the scope, users, topics, preliminary recommendations, and 3 systematic reviews: efficacy and safety of pre-surgical analgesia regarding to post-surgical pain, efficacy and safety of pre-emptive analgesia and pre-operative factors of post-operative pain. The level of evidence and grade of recommendation was established using the Oxford Centre for Evidence Based Medicine, and the level of agreement with the Delphi technique (2 rounds). The Delphi was extended to 39 orthopedics and anesthesiologists. The whole document was reviewed by all the experts. RESULTS: A total of 21 recommendations were produced. They include specific pharmacological treatment, as well as the evaluation and monitoring of patients on this treatment, and post-operative pre-emptive treatment. Agreement above 70% was reached in 19 recommendations. CONCLUSIONS: In patients undergoing total knee or hip replacement, a proper evaluation, follow-up, pharmacological and non-pharmacological treatment of predictors of poor surgical outcomes should be performed, especially those related to pre-operative pain. This can improve post-operative pain and surgery outcomes.

La geometría de la quilla condiciona el comportamiento de la bandeja tibial frente a fuerzas de torsión en prótesis totales de rodilla / The geometry of the keel determines the behaviour of the tibial tray against torsional forces in total knee replacement

El diseño de la quilla de una bandeja tibial es fundamental para la transmisión de la mayor parte de las cargas a las estructuras óseas periféricas, las cuales tienen mejores propiedades mecánicas reduciendo, de este modo, el riesgo de aflojamiento. El objetivo de este estudio es comparar el comportamiento de diferentes diseños de bandeja tibial ante cargas de torsión. Se modelizaron 4 componentes tibiales diferentes. La reconstrucción 3 D se llevó a cabo con el programa MIMICS. Los sólidos se generaron en SolidWorks. Se realizó el estudio por elementos finitos mediante Unigraphics. Se simuló una torsión de 6 Nm aplicada sobre los laterales de cada bandeja tibial. La bandeja tibial GENUTECH® con apoyo en el hueso trabecular periférico mostró un menor desplazamiento y menores tensiones transmitidos bajo fuerzas de torsión. Los resultados indican que la bandeja tibial con apoyo más periférico tienen un mejor comportamiento mecánico mejor frente a los otros diseños estudiados (AU)

The keel design of the tibial tray is essential for the transmission of the majority of the forces to the peripheral bone structures, which have better mechanical proprieties, thus reducing the risk of loosening. The aim of the present study was to compare the behaviour of different tibial tray designs submitted to torsional forces. Four different tibial components were modelled. The 3-D reconstruction was made using the Mimics software. The solid elements were generated by SolidWorks. The finite elements study was done by Unigraphics. A torsional force of 6 Nm. applied to the lateral aspects of each tibial tray was simulated. The GENUTECH® tibial tray, with peripheral trabecular bone support, showed a lower displacement and less transmitted tensions under torsional forces. The results suggest that a tibial tray with more peripheral support behaves mechanically better than the other studied designs (AU)

Rehabilitación domiciliaria postartroplastia total de rodilla: estudio coste-efectividad / Home-based rehabilitation after total knee arthroplasty: A cost-effectiveness study

Introducción: La rehabilitación domiciliaria permite a los pacientes intervenidos de artroplastia total de rodilla (ATR) volver antes a su domicilio y acelerar su reinserción comunitaria. Material y métodos: Estudio observacional simple, con incorporación consecutiva de pacientes desde noviembre del 2005 hasta mayo del 2008. Población de estudio: Pacientes remitidos al servicio domiciliario desde el Hospital Clínico de Barcelona post-ATR por gonartrosis. Intervención: Se realizó un programa de rehabilitación domiciliaria con evaluaciones antes del tratamiento y al alta, y seguimiento a los 6 meses. Se consideraron como variables de eficacia la variación en las puntuaciones del Western Ontario and McMaster Osteoarthritis (cuestionario WOMAC), el índice de Barthel (IB) y el balance articular. Se realizó una comparativa de costes según parámetros del Servei Català de la Salut. Se utilizó el test no paramétrico de Wilcoxon para comparar las puntuaciones del cuestionario WOMAC. Los datos cuantitativos fueron analizados por la t de Student. Resultados: Se reclutó a un total de 530 pacientes. El 78% de estos alcanzaron un grado de independencia con puntuación 100 según el IB, el arco de movimiento de flexión de rodilla fue superior a 100° en el 96,4% y la puntación media en todos los pacientes del cuestionario WOMAC fue de 13,48 (intervalo de confianza, 12,27-14,68). Se redujo la estancia media hospitalaria a 5,1 días, siendo el coste en el ámbito domiciliario la mitad que en el ambulatorio. Conclusión: La rehabilitación domiciliaria consigue disminuir la estancia hospitalaria con resultados funcionales óptimos y minimización de costes (AU)

Introduction: Home rehabilitation allows an earlier return to home in patients undergoing total knee arthroplasty. Material and methods: We performed a simple observational study with consecutive enrolment of patients from November 2005 to May 2008. Study population: Adult patients referred to the home-based rehabilitation service of Hospital Clinic in Barcelona after total knee arthroplasty for gonarthrosis. Intervention: We conducted a multidisciplinary home-based rehabilitation program with assessments before treatment, at discharge from rehabilitation and at 6 months follow-up. The outcomes measured were the Western Ontario and McMaster Universities Index (WOMAC), the Barthel Index (BI), and range of motion (ROM) scores. Costs were compared using parameters of the Catalan Health Service. Wilcoxon’s non-parametric test was used to analyze WOMAC outcomes. Quantitative data were analyzed using Student’s t test. Results: A total of 530 patients were recruited. Of these, 78% achieved a degree of independence, with a BI score of 100. The ROM for knee flexion was greater than 100◦ in 96.4% and the average rating of all the patients in the questionnaire WOMAC was 13.48 (CI: 12.27-14.68). The average length of hospital stay was reduced to 5.1 days, and the cost of home rehabilitation was half that in the outpatient setting. Conclusion: The home rehabilitation model reduces length of hospital stay and cost and has optimal functional results (AU)

[The geometry of the keel determines the behaviour of the tibial tray against torsional forces in total knee replacement]. / La geometría de la quilla condiciona el comportamiento de la bandeja tibial frente a fuerzas de torsión en prótesis totales de rodilla.

The keel design of the tibial tray is essential for the transmission of the majority of the forces to the peripheral bone structures, which have better mechanical proprieties, thus reducing the risk of loosening. The aim of the present study was to compare the behaviour of different tibial tray designs submitted to torsional forces. Four different tibial components were modelled. The 3-D reconstruction was made using the Mimics software. The solid elements were generated by SolidWorks. The finite elements study was done by Unigraphics. A torsional force of 6 Nm. applied to the lateral aspects of each tibial tray was simulated. The GENUTECH® tibial tray, with peripheral trabecular bone support, showed a lower displacement and less transmitted tensions under torsional forces. The results suggest that a tibial tray with more peripheral support behaves mechanically better than the other studied designs.

Consenso SECOT sobre artroplastia de rodilla dolorosa / SECOT consensus on painful knee replacement

En este estudio se valoran las opiniones de 21 expertos en cirugía de rodilla, mediante la metodología Delphi de cuestionarios en 2 rondas sucesivas, sobre 64 escenarios controvertidos que abarcan tanto el diagnóstico como el posible tratamiento de las artroplastias de rodilla dolorosas. El grado de consenso fue significativamente unánime en 42 ítems y el de disenso en 5, sin encontrar acuerdo en 17 de las cuestiones planteadas. A la luz de la evidencia científica publicada, los cirujanos que participaron demostraron un grado notable de información sobre las pruebas diagnósticas más rentables, aunque llama la atención la falta de confianza en la posibilidad de descartar una infección cuando la velocidad de sedimentación y la proteína C tienen valores normales, lo que ha demostrado en la literatura tener un alto valor predictivo negativo. Respecto a los tratamientos a emplear en las distintas situaciones, las respuestas del panel de expertos estuvieron mayoritariamente en consonancia con los datos de la bibliografía. Las conclusiones de este consenso pueden ayudar a otros cirujanos en el momento de enfrentarse a una prótesis de rodilla dolorosa (AU)

The opinions of 21 experts in knee surgery were evaluated in this study, using a DELPHI questionnaire method in two successive rounds, on 64 controversial scenarios that covered both the diagnosis and possible treatment of painful knee replacements. The level of consensus was significantly unanimous in 42 items and of the design in 5, with no agreement in 17 of the questions presented. light of the published scientific evidence, the surgeons who took part showed to have a notable level of information on the most effective diagnostic tests, although, it should be pointed out that there was a lack of confidence in the possibility of ruling out an infection when the erythrocyte sedimentation rate and the C-reactive protein were within normal values, which have been demonstrated in the literature to have a high negative predictive value As regards the treatments to employ in the different situations, the responses of the expert panel were mainly in agreement with the data in the literature. The conclusions of this consensus may help other surgeons when they are faced with a painful knee prosthesis (AU)

[SECOT consensus on painful knee replacement]. / Consenso SECOT sobre artroplastia de rodilla dolorosa.

The opinions of 21 experts in knee surgery were evaluated in this study, using a DELPHI questionnaire method in two successive rounds, on 64 controversial scenarios that covered both the diagnosis and possible treatment of painful knee replacements. The level of consensus was significantly unanimous in 42 items and of the design in 5, with no agreement in 17 of the questions presented. light of the published scientific evidence, the surgeons who took part showed to have a notable level of information on the most effective diagnostic tests, although, it should be pointed out that there was a lack of confidence in the possibility of ruling out an infection when the erythrocyte sedimentation rate and the C-reactive protein were within normal values, which have been demonstrated in the literature to have a high negative predictive value As regards the treatments to employ in the different situations, the responses of the expert panel were mainly in agreement with the data in the literature. The conclusions of this consensus may help other surgeons when they are faced with a painful knee prosthesis.

[Use of trabecular metal in total knee arthroplasty in severely and morbidly obese patients (BMI > 35 kg/m2)]. / Utilización del metal trabecular en artroplastía total de rodilla en pacientes obesos graves y mórbidos (IMC >35 kg/m2).

The use of trabecular metal in the tibial surface may increase prosthetic survival in the population with severe or morbid obesity (BMI > 35 kg/m2). A prospective, descriptive study was conducted of patients with a BMI > 35 kg/m2 who underwent total knee replacement with a prosthesis with trabecular metal. Minimal follow-up was two years. The statistical analysis was done with Student's t test; the Knee Society Score and the Western Ontario and McMaster Universities Osteoarthritis Index were applied preoperatively and postoperatively. The chi2 test was applied to the BMI values relating them with more or less radiolucent images. The total number of patients was 39, but three were excluded for not having the radiographic follow-up. Mean follow-up was 34 months (25-43); 35 were females, mean age was 69.4 years (57-81), mean BMI was 39.43 kg/m2 (35-55). All patients had grades 3 and 4 tricompartmental arthrosis. The KSS (R and F) and WOMAC scales, with a 95% confidence interval, showed a statistically significant improvement in the assessment of preoperative results and at the end of the followup. Only a few studies measure long-term implant survival. Most authors define survival as the absence of the need to revise prosthetic implants. The end point of survival is the removal or exchange of prosthetic components. Trabecular metal (TM) is currently used in orthopedic surgery and its clinical applications are increasing more and more with good results.

Secondary patellar resurfacing in the treatment of patellofemoral pain after total knee arthroplasty.

PURPOSE: This paper reports a prospective review of patients who, between 2004 and 2007, underwent secondary patellar resurfacing (SPR) due to anterior knee pain after a primary total knee arthroplasty (TKA). The aim was to evaluate the clinical outcomes obtained with the SPR and to compare them with radiological findings. METHODS: A total of twenty-seven consecutive patients met the inclusion criteria. There were twenty-three (85%) women and four (15%) men with a median age of 70 years. The patients were evaluated before and after the surgery with the same functional scores and radiological parameters. Bone scintigraphy was also used in the assessment, and a CT-scan was performed in order to evaluate the femoral component rotation. The median time between TKA and SPR was 18 months. RESULTS: With a median follow-up of 23 months, seventeen patients (63%) reported a clear subjective improvement after SPR, and patellofemoral scores (primary outcome measure), KSS and WOMAC (secondary outcome measures) showed a statistically significant improvement following the procedure. There were no significant changes after SPR in the Insall-Salvati ratio, the lateral patellar displacement or the lateral patellar tilt. The mean time between TKA and SPR had no statistically significant effect on outcome. The bone scintigraphy revealed increased patellar uptake in seven cases, but this was not related to subsequent improvement after SPR. Rotational computed tomography showed a median internal rotation of the femoral component of 1º. The complications observed were a patellar component loosening and an acute post-infection. CONCLUSION: No clinical or radiological parameter was found to be related to the final outcome after SPR. There was a discrepancy between functional scale scores and the patient's subjective satisfaction.

Outcome and predictors of treatment failure in early post-surgical prosthetic joint infections due to Staphylococcus aureus treated with debridement.

Experience with debridement and prosthesis retention in early prosthetic joint infections (PJI) due to Staphylococcus aureus is scarce. The present study aimed to evaluate the outcome and predictors of failure. Patients prospectively registered with an early PJI due to S. aureus and 2 years of follow-up were reviewed. Demographics, co-morbidity, type of implant, clinical manifestations, surgical treatment, antimicrobial therapy and outcome were recorded. Remission was defined when the patient had no symptoms of infection, the prosthesis was retained and C-reactive protein (CRP) was ≤ 1 mg/dL. Univariate and multivariate analysis were performed. Fifty-three patients with a mean ± SD age of 70 ± 10.8 years were reviewed. Thirty-five infections were on knee prosthesis and 18 were on hip prosthesis. The mean ± SD duration of intravenous and oral antibiotics was 10.6 ± 6.7 and 88 ± 45.9 days, respectively. After 2 years of follow-up, 40 (75.5%) patients were in remission. Variables independently associated with failure were the need for a second debridement (OR 20.4, 95% CI 2.3-166.6, p 0.006) and a CRP > 22 mg/dL (OR 9.8, 95% CI 1.5-62.5, p 0.01). The onset of the infection within the 25 days after joint arthroplasty was at the limit of significance (OR 8.3, 95% CI 0.8-85.6, p 0.07). Debridement followed by a short period of antibiotics is a reasonable treatment option in early PJI due to S. aureus. Predictors of failure were the need for a second debridement to control the infection a CRP > 22 mg/dL and the infection onset within the first 25 days after joint arthroplasty.

Intramedullary versus extramedullary tibial cutting guide in severely obese patients undergoing total knee replacement: a randomized study of 70 patients with body mass index >35 kg/m2.

BACKGROUND: Patients with obesity have an increased risk of osteoarthritis of the knee, which can lead to the need for total knee replacement (TKR). TKR may be more complex in obese patients and the correct orientation of the implant is more difficult. We selected patients with body mass index (BMI) >35 kg/m(2) undergoing TKR and studied the utility of an intramedullary tibial cutting guide in facilitating the correct orientation of the tibial implant. METHODS: Seventy patients with BMI >35 kg/m(2) were selected for a prospective, randomized study. Patients were divided into two groups: In group 1 (n=31), the tibial component was implanted using the aid of a intramedullary tibial guide. In group 2 (n=39), the tibial component was implanted using the aid of an extramedullary tibial cutting guide. RESULTS: The two groups were comparable with respect to age, BMI, and degree of preoperative deformity. Mean age was 69.35 in group 1 and 70.06 in group 2. Group 1 had a mean BMI of 39.84 kg/m(2) and group 2 of 40.05 kg/m(2). Postoperative orientation of the femur and tibia and the mechanical axis were within the normal range in both groups. A statistically significant difference between the two groups was observed in tourniquet time, which was longer in group 2 than in group 1 (p=0.038). CONCLUSION: Two types of guide were compared in correctly orienting the tibial component of the TKR in patients with a BMI >35 kg/m(2). The lesser tourniquet time in the group in which the intramedullary guide was used suggest its usefulness because the positioning and orientation of the tibial cut was carried out more rapidly and anatomical references were not needed for correct orientation, as it is guided by the anatomical axis of the tibia. The use of the intramedullary guide reduces surgical time in these patients.

Of the in vivo behavior of calcium phosphate cements and glasses as bone substitutes.

The use of injectable self-setting calcium phosphate cements or soluble glass granules represent two different strategies for bone regeneration, each with distinct advantages and potential applications. This study compares the in vivo behavior of two calcium phosphate cements and two phosphate glasses with different composition, microstructure and solubility, using autologous bone as a control, in a rabbit model. The implanted materials were alpha-tricalcium phosphate cement (cement H), calcium sodium potassium phosphate cement (cement R), and two phosphate glasses in the P(2)O(5)-CaO-Na(2)O and P(2)O(5)-CaO-Na(2)O-TiO(2) systems. The four materials were osteoconductive, biocompatible and biodegradable. Radiological and histological studies demonstrated correct osteointegration and substitution of the implants by new bone. The reactivity of the different materials, which depends on their solubility, porosity and specific surface area, affected the resorption rate and bone formation mainly during the early stages of implantation, although this effect was weak. Thus, at 4 weeks the degradation was slightly higher in cements than in glasses, especially for cement R. However, after 12 weeks of implantation all materials showed a similar degradation degree and promoted bone neoformation equivalent to that of the control group.

Relationship between knee anthropometry and surgical time in total knee arthroplasty in severely and morbidly obese patients: a new prognostic index of surgical difficulty.

BACKGROUND: Total knee arthroplasty (TKA) in patients with severe and morbid obesity is one of the current challenges in prosthetic knee surgery. The body mass index (BMI) is used to identify patients who may present difficulties during surgery and postoperative complications. We carried out a prospective study with an initial hypothesis that BMI is not associated with tourniquet time in obese patients undergoing TKA and that some anthropometric parameters may be useful in predicting tourniquet time in severely and morbidly obese patients. METHODS: One hundred consecutive patients diagnosed with knee osteoarthritis with BMI > or =35 kg/m(2) scheduled for TKA were prospectively studied. Suprapatellar, infrapatellar, and supra/infrapatellar anthropometric indexes were calculated before surgery. The tourniquet time was determined. RESULTS: The mean BMI was 39.81 kg/m(2) (SD +/- 3.75). A total of 58% of patients were classified as class III obesity (BMI 35-39.99) and 42% as class IV (BMI > or = 40) Mean tourniquet time was 41.67 min (SD +/- 9.26). There was no association between the BMI and tourniquet time. The suprapatellar index was negatively associated with tourniquet time (p < 0.038). DISCUSSION: The BMI is not the only parameter that should be considered in order to identify severely and morbidly obese patients who may have more surgical difficulties during TKA. Preoperative determination of the suprapatellar index helped us to classify these patients according to the morphology of the knee and predicted a longer tourniquet time and, therefore, greater surgical difficulty, in patients with a suprapatellar ratio below 1.6 in this study.

Effectiveness and safety of tranexamic acid administration during total knee arthroplasty.

BACKGROUND: The administration of tranexamic acid (TA) is associated with a decrease in the number of red blood cell (RBC) units transfused. However, concerns about its safety have hindered its broader use. STUDY DESIGN AND METHODS: We evaluated the effect of TA on RBC transfusion and thromboembolic complications in total knee arthroplasty. We retrospectively studied 414 patients, 215 immediately before introducing TA treatment (control group) and after, in 199 patients without history of thromboembolic diseases (TA group). In a subgroup of patients, a lower extremities contrast venography was performed. RESULTS: Fifty-four per cent of control group patients were transfused with RBC while only 17.6% of TA group patients received RBCs. In the TA that group, those transfused received less units (2.83 vs. 1.89), showed smaller mean calculated perioperative blood loss and haemoglobin values at discharge were higher compared to control group (10.1 vs. 9.3 g/dl). Thromboembolic complications were diagnosed in 2.8% of the patients in the control group and in 1.5% in the TA group. Asymptomatic distal deep venous thrombosis was found in 54 (14.8%) of TA group patients and 54 (30.1%) of control patients. TA administration reduced the expenditure for RBC transfusion plus the cost of TA from 148.94 to 33.87 euro per patient. CONCLUSION: Routine administration of TA during total knee arthroplasty to patients without history of thromboembolic disease is associated with a 67% reduction in RBC transfusions and, in those transfused, with a reduction in the number of units administered. TA treatment was not associated with an increase in thromboembolic complications. Transfusion costs are significantly reduced.

Prótesis total de rodilla rígida: factores etiológicos y tratamiento / The stiff total knee prosthesis: etiological factors and treatment

Introducción. La rigidez articular tras una prótesis total de rodilla es una complicación rara, aunque muy molesta para el paciente.Revisión de conceptos. En este artículo hemos llevado a cabo una puesta al día de la etiología y del tratamiento de la rigidez de las prótesis de rodilla.Conclusión. El conocimiento de las causas de la rigidezsuele ayudarnos a obtener mejores resultados. Sin embargo, en estos casos es raro lograr la movilidad completa

Introduction. Although rare, articular stiffness after a total knee arthroplasty is an extremely disabling complication for the patient.Concept review. This paper contains an update on the etiology and treatment of prosthetic knee stiffness.Conclusion. The knowledge of the causes leading to stiffness can help us obtain better results. However, it is not common to achieve full mobility in these cases